Added ConvertTo<*> methods in exec.cpp, and eval_<*> methods in express.cpp
Added Eval(Optional)ExprAs<Type>() methods in exec.cpp, where <Type> = BooleanRef, DataRef, etc
Updated MCChoose::exec(ep) to MCChoose::exec_ctxt(ctxt)
Updated MCDo::exec(ep) to MCDo::exec_ctxt(ctxt)
Updated MCDoMenu::exec(ep) to MCDoMenu::exec_ctxt(ctxt)
Updated MCFind::exec(ep) to MCFind::exec_ctxt(ctxt)
Updated MCGet::exec(ep) to MCGet::exec_ctxt(ctxt)
Updated MCQuit::exec(ep) to MCQuit::exec_ctxt(ctxt) and fixed a bug in previous commit (in MCGet::exec_ctxt)
Updated MCSet::exec(ep) to MCSet::exec_ctxt(ctxt)
Updated MCWait::exec(ep) to MCWait::exec_ctxt(ctxt)
Updated MCInclude::exec(ep) to MCInclude::exec_ctxt(ctxt)
Updated MCLaunch::exec(ep) to MCLaunch::exec_ctxt(ctxt)
Fixed errors to compile on mobile
Updated MCLoad::exec(ep) to MCLoad::exec_ctxt(ctxt) plus a correction in MCLaunch::exec_ctxt
Updated MCUnload::exec(ep) to MCUnload::exec_ctxt(ctxt)
Updated MCPost::exec(ep) to MCPost::exec_ctxt(ctxt)
Updated MCRecord::exec(ep) to MCRecord::exec_ctxt(ctxt)
Updates after feedback on MCDo::exec_ctxt(ctxt)
Fixed an error in MCRecord::exec_ctxt(ctxt) (I had forgotten an ! inside an if condition)
Replaced ctxt.EvalOptionalExprAs<Type> with ctxt.EvalExprAs<Type> where necessary